Leverage Marketing
#8 in Austin

I've used them at three different companies in the tech industry, they are excellent on search - both paid and organic. Excellent communication, very friendly staff, attentive account manager, and most of the employees have been with the company for YEARS. Low churn is a good leading indicator for any of these types of agencies, but I've had about 7 years experience with these guys. They'll tell you what's wrong, what they'll do, and how long they say it's going to take. I have had the pleasure of seeing them repeat the process with great success at different firms, so I know I didn't just get lucky. Give them a shout.